With the deployment of Long Term Evolution (LTE) the number of different radio access networks used side by side is further increasing. Thereby, it is a challenge to monitor, trouble-shoot and optimize not only one individual network but also the combination of networks, since a mobile user may change the cell or even the network during a single session.
Currently, Performance Management (PM) functions of radio access networks are used for monitoring, trouble-shooting and optimizing of networks. Monitoring is needed to detect and prevent any degradation or fault during the operation. Trouble-shooting functions aid to find the cause of an error in the complex system. Optimization functions are used to improve network quality and improve the utilization of the network resources.
Several PM functions trigger radio measurements which can be implemented for mobile stations and base stations. The primary goal of these measurements is to facilitate the mobility between cells, e.g. to allow handover within cells of the same radio network or between cells of different radio networks. For example, measurements are triggered by PM functions, wherein downlink measurements are performed by mobile equipment, such as mobile stations, and uplink measurements are performed by base stations.
Some PM functions also use and activate periodic radio measurements, the result of which is recorded as a recording and provided to a network node or support apparatus. For example, PM functions activate the measurement of radio parameters of specific frequency channels or channel codes or scan the frequency spectra or code range. The recordings are classified in recording types. Examples of such recording types are BCCH Allocation Recording (BAR) and the Radio Interference Recording (RIR) functions in GSM, or Radio Environment Statistics (RES) measurements in Wireless Regional Area Networks (WRAN). PM functions for LTE radio measurements are under specification in 3GPP TS 36.214.
The measurement data may be collected in statistical counters or reported in PM events. The counters and events generated by the recordings can be collected in files for a Result Output Period (ROP) in a network node, such as Base Station Controller (BSC) (in GSM network), Radio Network Controller (RNC) (in WCDMA network), or eNodeB (in LTE network). ROP files may then be sent after the ROP periodically to Operating Support System (OSS) or another network management node. It is also possible to use streaming interfaces to provide the network management node with PM events. The counters and events can then be processed in the network management node. Events, which are generated by recordings of measurement data activated by a PM function, can highly load network nodes, such as a base station or BSC, and an OSS.
A PM function may include the functionality of the OSS side, constituting an application at the OSS side, and a recording function in the node. The recording function in the node includes the measurement function and collecting/saving the measurement data by carrying out a recording. The data is then analyzed by the PM function.
Currently, executions of PM functions and thus data measurements and their recordings are scheduled manually based on the experience of Radio Network Optimization (RNO) engineers and there is no adequate procedure for planning the recordings and ensure the required resources in the nodes for the execution of PM functions. Further, there is currently no tool to estimate the load at a network node generated by PM functions and to compare the load to characteristics measured at the network node side, such as the OSS side to determine the capability in coping with scheduled PM functions at the network node.
Different RNO functions, a subset of PM functions, share common recording functions of GSM, WRAN and LTE networks. It is a general limitation of a radio network system that parallel recordings using the same PM functions with possibly different parameters cannot be performed for overlapping selected cell sets so that the recordings have to be scheduled, e.g. manually by an RNO engineer. Additionally, functions that activate periodic measurements generate high load on the network as well so that the number of selected cell sets and the number of possible parallel recordings is limited.
On the one hand, it is desirable for operators to obtain as much information about the network as possible, and thus to run PM functions continuously to obtain measurement data for the whole network and for different time periods. However, on the other hand, it has to be ensured that network nodes and particularly the OSS server are not overloaded. Manually scheduled recordings by an RNO engineer are often insufficient to optimally meet these requirements and may lead to inadequate recordings, insufficient data and server and/or network overload.
These problems are even more severe in large networks, in which the network management is divided into multiple OSSs which may be segmented based on time zones. Accordingly, such segmentation may lead to high loads on each OSS server in busy business hours and low load at night where only a small part of the OSS server capacity is used.